bp-sitewide-activity-stream-for-friends.php

<?php
/**
 * Sidewide activity stream only for friends.
 *
 * @param  array $args Arguments.
 */
function wbcom_friends_only_activity_args( $args ) {

	if ( ! bp_is_activity_directory() || ! is_user_logged_in() || ! empty( $args['scope'] ) ) {
		return $args;
	}

	$user_id = get_current_user_id();

	$user_ids = friends_get_friend_user_ids( $user_id );

	array_push( $user_ids, $user_id );

	$args['user_id'] = $user_ids;

	return $args;

}
add_filter( 'bp_after_has_activities_parse_args', 'wbcom_friends_only_activity_args' );